Example 30
Six balls are drawn successively from an urn containing 7 red and 9 black balls. Tell whether or not the trials of drawing balls are Bernoulli trials when after each draw the ball drawn is
(i) replaced
Let,
Probability of success = Probability of drawing red ball
p = 7﷮16﷯
Here,
• Number of trial is finite
• There are two outcomes
(3) Probability of success (p) does not change in trial, as Probability of drawing red ball is same
Hence, it is a Bernoulli trial
Example 30
Six balls are drawn successively from an urn containing 7 red and 9 black balls. Tell whether or not the trials of drawing balls are Bernoulli trials when after each draw the ball drawn is
(ii) not replaced in the urn.
Let
Probability of success = Probability of drawing red ball
In first trial
7 red & 9 black ball
Probability drawing red (p) = 7﷮16﷯
In second trial
Since, Probability of success (p) changes in all trials,
Hence, the trials are not Bernoulli trials.